Existentialism Is a Humanism is a piece of literature published in 1946 and produced by Jean-Paul Sartre, one of the most influential philosophers of the 20th century. It was based on his famous lecture given at Club Maintenant in Paris, on 29 October 1945.
This work popularized the phrase "existence precedes essence," present in his magnum opus, Being and Nothingness, published in 1943. The phrase in question exemplifies the main belief of Sartrean existentialism, that human beings exist in the world before having a defined meaning to their existence. Existentialism Is a Humanism is an attempt to translate these ideas to the general public, given the complexity of his previous works, and to defend his conception of existentialism from popular criticisms.
The lecture was one of the main factors that launched Sartre's career as a public intellectual and included his ideas in mainstream thought. Indeed, alongside Simone de Beauvoir and Michel Foucault, Sartre became one of the intellectual "celebrities" in the mid-to-late 20th century in France.
However, he even later admitted to regretting publishing his lecture, considering it a simplification of his thought that led to many misinterpretations of existentialism. However, Walter Kaufmann, a fellow philosopher, commented that it was "a brilliant lecture which bears the stamp of the moment."